The present disclosure generally relates to aircraft environmental control systems and, more particularly, to a lockout tool for an air cycle machine utilized as part of an aircraft environmental control system.
Conventional aircraft environmental control systems (ECS) incorporate an air cycle machine (ACM), also referred to as an air cycle cooling machine, for cooling and dehumidifying air supplied to an aircraft cabin. ACMs commonly include at least one turbine and a compressor spaced axially at intervals on a common shaft. The turbine(s) and compressor are supported for rotation about the axis of the shaft by one or more bearing assemblies.
On aircraft powered by turbine engines, the air to be conditioned in the air cycle machine is typically compressed air bled from one or more compressor stages of a turbine engine. In conventional systems, this bleed air is passed through the air cycle machine compressor, where it is further compressed, then passed through a condensing heat exchanger to cool the compressed air. The heat exchanger sufficiently condenses moisture thereby dehumidifying the air. The dehumidified compressed air is then expanded in one of the turbines to extract energy from the compressed air so as to drive the shaft and also to cool the expanded turbine exhaust air as it is supplied to the cabin as conditioned cooling air.
During normal operation of an ACM, the shaft is typically driven to rotate as noted above. However, during certain failure modes, the shaft may continue to rotate without being directly driven. An aircraft may continue to fly safely with a failed ACM but continued rotation of the shaft of a failed ACM can lead to undesirable results, such as damage to other parts within the ACM, release of debris, odors, and the like.